Lap desk



FIG. 1 is a top perspective view of the design for a lap desk.

FIG. 2 is a top view of the design for a lap desk.

FIG. 3 is a top edge view of the design for a lap desk.

FIG. 4 is a bottom edge view of the design for a lap desk.

FIG. 5 is a left edge view of the design for a lap desk.

FIG. 6 is a right edge view of the design for a lap desk; and,

FIG. 7 is a bottom view of the design for a lap desk. 

The ornamental design for a lap desk, as shown and described. 